The present invention relates to a sheet delivery mechanism, and more particularly to a sheet delivery mechanism including suction means such suction cups or the like displaceable to attract a sheet such as a stimulable phosphor sheet, and a feed roller pair displaceable toward the sheet to receive the sheet from the suction means, so that the sheet can reliably be picked up or delivered from a cassette or a magazine simply by displacing the suction means and the roller pair.
There has recently been known a radiation image information recording and reproducing system for producing the radiation-transmitted image of an object using a stimulable phosphor material capable of emitting light upon exposure to stimulating rays. When a certain phosphor is exposed to a radiation such as X-rays, .alpha.-rays, .beta.-rays, .gamma.-rays, cathode rays, or ultraviolet rays, the phosphor stores a part of the energy of the radiation. When the phosphor exposed to the radiation is subsequently exposed to stimulating rays such as visible light, the phosphor emits light in proportion to the stored energy of the radiation. The phosphor exhibiting such a property is referred to as a "stimulable phosphor".
In the radiation image recording and reproducing system employing such a stimulable phosphor, the radiation image information of an object such as a human body is stored in a sheet having a layer of stimulable phosphor, and then the stimulable phosphor sheet is scanned with stimulating rays such as a laser beam to cause the stimulable phosphor sheet to emit light representative of the radiation image. The emitted light is then photoelectrically detected to produce an image information signal that is electrically processed for generating image information which is recorded as a visible image on a recording medium such as a photosensitive material or displayed as a visible image on a CRT or the like.
The radiation image recorded on the stimulable phosphor sheet is read in the radiation image recording and reproducing system as follows:
The radiation image recording and reproducing system includes an image reader for two-dimensionally scanning the stimulable phosphor sheet with a light beam such as a laser beam to cause the stimulable phosphor sheet to emit light, and detecting the light in time series with a light detector such as a photomultiplier to obtain image information. The stimulable phosphor sheet is usually two-dimensionally scanned by mechanically feeding the stimulable phosphor sheet in an auxiliary scanning direction, and simultaneously deflecting the light beam and applying the deflected light beam to the stimulable phosphor sheet in a main scanning direction substantially normal to the auxiliary scanning direction.
An object to be imaged is exposed to radiation, which passes through the object to record a radiation image of the object on a stimulable phosphor sheet stored in a cassette. The cassette storing the stimulable phosphor sheet is then loaded into an image reader, and then the stimulable phosphor sheet is removed from the cassette by a sheet delivery mechanism including a suction cup and fed to a scanning position in which the stimulable phosphor sheet is two-dimensionally scanned by a light beam.
One general arrangement of such a cassette is illustrated in FIG. 1 of the accompanying drawings.
As shown in FIG. 1, a cassette 2 comprises a casing defining a chamber 4 for storing a stimulable phosphor sheet S therein, and a lid 10 swingably mounted on one end of the casing 6 by means of a hinge 8.
The cassette 2 with the stimulable phosphor sheet S stored therein is loaded into an image reader 12, for example. The lid 10 is opened by a suction cup 14 in the image reader 12 to open the chamber 4 in the image reader 2. Then, a sheet delivery mechanism including a suction cup 16 is operated to attract the stimulable phosphor sheet S in the casing 6 and, the attracted stimulable phosphor sheet S is fed to a scanning reading unit through a feed mechanism (not shown).
When the stimulable phosphor sheet S is to be picked up from the cassette 2, the stimulable phosphor sheet has to be removed, as if fanned, by the sheet delivery mechanism in order to prevent the stimulable phosphor sheet S from engaging a front wall 6a of the casing 6. The sheet delivery mechanism is therefore considerably complex in structure in order to cause the suction cup 16 to move along a path for giving a desired removing or fanning action to the stimulable phosphor sheet S.